Knife holder of roller cutting machines



June 1, 1965 P. wlNGEN KNIFE HOLDER OF ROLLER CUTTING MACHINES Filed July 23, 1962 INVENTOR: Peter lA/njen United States Patent O 4 claims. (l. :i3-469) This invention relates to a knife holder of roller cutting machines which is actuated by a pressure medium.

An object of the present invention is to improve prior art constructions of such machines.

The present invention is concerned with a device having separate spring-engaged pistons for lowering a circular knife upon the material to be cut and for the side setting of this circular knife relatively to a lower knife, whereby a common connection for a pressure medium is provided for the two pistons and the spring pressure upon the pistons is so adjusted that when the pressure medium is admitted the lowering operation takes place lirst and is followedby the setting operation, and whereby the pistn rod for the piston to be lowered contains an axial connecting bore for the pressure chambers belonging to the two pistons.

The most important advantage of such a device is that any possible damage to the two circular knives operating opposite each other, is effectively avoided by carrying out the lowering movement prior to the setting movement with only one conduit for the pressure medium and only one actuating valve; however, this advantage is effectively attained only by providing considerable differences in the spring tensions exerted upon the two pistons, since when the movement begins, considerable adhesion friction taking place between the piston and the guiding means for the piston, and which can not be effectively adjusted, is added to the spring pressure.

However, a substantial adjustment of spring pressure requires a corespondingly large counter pressure of the pressure medium with the result that the economic ethciency of the device is affected.

Another object of the present invention is to eliminate the above-described drawbacks.

In accordance with the present invention the beginning of the lowering movement prior to the setting movement is reliably assured despite small spring pressures and a correspondingly small setting of the spring load, through the provision of a radial valve bore which establishes a communication between the connecting bore of the piston rod and the pressure chamber of the lowering piston for the lowering operation, the communication being interrupted when the lowering piston is in its position of rest.

In accordance with a further development of the present invention, the detrimental effect of piston friction, particularly during the setting movement, is diminished through the use of rigid pistons with grooved-in sealing rings instead of pot collars used in prior art and producing a great amount of friction.

Further features of the present invention pertain to an easier adjustment of the lowering operation by arrangeing the spindle setting upon that side of the lowering cylinder which is away from the cutting head, since that side is easily accessible and not exposed to any accidents; they pertain also to a more compact construction of the setting device for the angle of incidence of the cutting head, so that the length of the lowering stroke for a device of the same size is increased; finally, they pertain to the replacement of prior art retaining rings for the circular knife by plate springs which assure a secure setting even ICC when the device is subjected to centrifugal forces produced by the rotating knife hubs.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings showing, by way of example, a preferred embodiment of the inventive idea.

In the drawings:

FIGURE l is an axial section through a device constructed in accordance with the principles of the present invention.

FIGURE 2 is a side view of the device shown in FIG- URE 1.

The device shown in the drawings includes a knife head 1 having a hub 3 which is supported by ball bearings 2; a circular knife 4 is replaceably mounted upon the circumferential surface of the hub 3 and is engaged by plate springs 6 which are held by shoulders 5 and which press the knife 4 against a counter shoulder 7.

The knife head 1 can be set by moving it to the right (looking in the direction of FIG. l) by means of a rod 8 connected with a piston 1t) which is the setting piston. The piston 10 carries a sealing ring 9 which is embedded therein. The movement of the piston 1i) caused by the pressure medium, is opposed by a spring 12 and may continue until the piston strikes an adjustable stop 11.

The knife head 1 is firmly connected with a piston rod 13 of the lowering piston 14; an axial bore 15 in the piston rod 13 connects the pressure chamber 16 of the casing 34 enclosing the lowering piston 14 with the pressure chamber 17 of casing 35 enclosing the setting piston 10. The piston 14- is engaged by a spring 18. The return spring 12 of the setting piston 161 is stronger, by comparison with the corresponding piston area, than the pressure exerted by the return spring 18 of the lower piston 14. The pressure medium is introduced into the chamber 16 through an inlet 33 of a cover 39.

Thus when the pressure medium is effective, the knife head 1 will be lowered first and set afterwards. When pressure of the pressure medium is diminished, movements take place in the reverse order. The correct sequence of these movements is assured by the radial valve bore 26 which is connected with the axial bore 15 and which provides a connection between the pressure chamber 17 of the setting piston and the pressure chamber 16 of the lowering piston through the bore 15 only after the beginning of the lowering movement, when the adhesion friction of means guiding the lowering piston has been overcome already.

The extent of the lowering depth can be adjusted by nuts 21 which are mounted upon screw threads 22 of an extension of the rod 13 of the lowering piston; this end of the rod 13 projects upwardly outside of the casing. Since the piston rod 13 is comparatively thick, the screw threads 22 can be conveniently surface hardened and will not affect the space available for the lowering operation between t-he cylinder of the lowering piston and the cutting head 1.

For the same reasons the rod 13 of the lowering piston is so guided that it cannot rotate. The rod 13 extends through a lower cover 23 which is attached by screws 26 to the casing 34 and which can be adjusted angularly by means of circumferential slots. The rotation of the rod 13 is prevented by a wedge 25 having a convex back fitting firmly into a correspondingly shaped concave recess in the rod 13, if necessary, with the additional use of a countersunk screw 31; the outer prismatic surfaces of the wedge 25 are guided in an axial groove of the lower cover 23.

The operation of the device is apparent from the above description.

it is apparent that the example shown above has been given solely by way of illustration and not by way of W limitation, and that it is capable of many variations and modifications. All such variations and modifications are to be included within the scope of the presentl invention.

What is claimed is:

1. A pressure medium-actuated knife holder of a roller cutting machine, said knife holder comprising, in combination with a single circular knife, a hub carrying said knife, a piston rod connected with said hub and extending transversely to said circular knife for the side setting of said knife, a piston connected with said piston rod, a spring engaging said piston, a casing enclosing said piston and said spring and having a pressure chamber, another piston rod connected with said casing and extending substantially perpendicularly to the first-mentioned piston rod, another piston connected with the secondmentioned piston rod and movable from a position of rest for the lowering of said knife, another spring engaging the second-mentioned piston, another casing enclosing the second-mentioned piston and the second-mentioned spring and having a pressure chamber and a single pressure medium inlet communicating with the secondmentioned pressure chamber, the second-mentioned piston rod having an axial bore communicating with the first-mentioned pressure chamber and a radial valve bore communicating with said axial bore, said radial valve bore being devoid of communication with the secondmentioned pressure chamber when the second-mentioned piston rod is in its said position of rest and establishing a communication with the second-mentioned pressure chamber when the second-mentioned piston is lowered from said position of rest to supply the pressure medium through said single inlet to the two pressure chambers, the two springs being of such sttrength that when pressure medium is introduced the lowering of said knife takes place prior to the side setting thereof, while when pressure of the pressure medium is released a reverse side movement of the knife takes place prior to the raising thereof, and at least one plate spring adjustably engaging said knife and said hub.

2. A knife holder in accordance with claim 1, wherein the second-mentioned casing comprises a cover containing said single pressure medium inlet, the secondmentioned piston rod having a free end extending beyond said cover, said free end having a threaded portion, and at least one nut carried by said threaded portion and adapted to engage said cover to limit the lowering movement of the second-mentioned piston.

3. A pressure medium-actuated knife holder of a roller cutting machine, said knife holder comprising, in combii nation with a circular knife, a hub carrying said knife, a piston rod connected with said hub and extending transversely to said circular knife for the side setting of said knife, a piston connected with said piston rod, a spring engaging said piston, a casing enclosing said piston and said spring and having a pressure chamber, another piston rod firmly connected with said casing and extending substantially perpendicularly to the first-mentioned piston rod, a wedge having a convex surface firmly tting into a correspondingly shaped concave recess formed in the second-mentioned piston rod, another piston connected with the second-mentioned piston rod and movable from a position of rest for the lowering of said knife, another spring engaging the second-mentioned piston, another casing enclosing the second-mentioned piston and the second-mentioned spring and having a pressure chamber and a single pressure medium inlet communicating with the second-mentioned pressure chamber, a lower cover facing the first-mentioned casing and circumferentially adjustably screwed to the second-mentioned casing, said lower cover having an axial groove for the guiding of said wedge, the second-mentioned piston rod having an axial bore communicating with the first-mentioned pressure chamber and a radial valve bore communicating with V said axial bore, said radial valve bore being devoid of communication with the second-mentioned pressure chamber when the second-mentioned piston rod is in its said position of rest and establishing a communication with the second-mentioned pressure chamber when the second-mentioned piston is lowered from said position of rest to supply the pressure medium through said single inlet to the two pressure chambers, the two springs being of such strength that when pressure medium is introduced the lowering of said knife takes place prior to the side setting thereof.

4. A knife holder in accordance with claim 3, comprising a countersunk screw firmly connecting said wedge with the second-mentioned piston rod.

References Cited by the Examiner UNITED STATES PATENTS 2,565,305 8/51 Godfriaux 82-2l.1 X 2,571,201 lO/Sl Clem 83-501 X 2,895,553 7/59 Gelleke 83-469 3,069,961 l2/62 Baubles 85-1y ANDREW R. JUHASZ, Primary Examiner. DONALD R. SCHRAN, Examiner. 

1. A PRESSURE MEDIUM-ACTUATED KNIFE HOLDER OF A ROLLER CUTTING MACHINE, SAID KNIFE HOLDER COMPRISING, IN COMBINATION WITH A SINGLE CIRCULAR KNIFE, A HUB CARRYING SAID KNIFE, A PISTON ROD CONNECTED WITH SAID HUB AND EXTENDING TRANSVERSELY TO SAID CIRCULAR KNIFE FOR THE SIDE SETTING OF SAID KNIFE, A PISTON CONNECTED WITH SAID PISTON ROD, A SPRING ENGAGING SAID PISTON, A CASING ENCLOSING SAID PISTON AND SAID SPRING AND HAVING A PRESSURE CHAMBER, ANOTHER PISTON ROD CONNECTED WITH SAID CASING AND EXTENDING SUBSTANTIALLY PERPENDICULARLY TO THE FIRST-MENTIONED PISTON ROD, ANOTHER PISTON CONNECTED WITH THE SECONDMENTIONED PISTON ROD AND MOVABLE FROM A POSITION OF REST FOR THE LOWERING OF SAID KNIFE, ANOTHER SPRING ENGAGING THE SECOND-MENTIONED PISTON, ANOTHER CASING ENCLOSING THE SECOND-MENTIONED PISTON AND THE SECOND-MENTIONED SPRING AND HAVING A PRESSURE CHAMBER AND A SINGLE PRESSURE MEDIUM INLET COMMUNICATING WITH THE SECONDMENTIONED PRESSURE CHAMBER, THE SECOND-MENTIONED PISTON ROD HAVING AN AXIAL BORE COMMUNICATING WITH THE FIRST-MENTIONED PRESSURE CHAMBER AND A RADIAL VALVE BORE COMMUNICATING WITH SAID AXIAL BORE, SAID RADIAL VALVE BORE BEING DEVOID OF COMMUNICATION WITH THE SECONDMENTIONED PRESSURE CHAMBER WHEN THE SECOND-MENTIONED PISTON ROD IS IN ITS SAID POSITION OF REST AND ESTABLISHING A COMMUNICATION WITH THE SECOND-MENTIONED PRESSURE CHAMBER WHEN THE SECOND-MENTIONED PISTION IS LOWERED FROM SAID POSITION OF REST TO SUPPLY THE PRESSURE MEDIUM THROUGH SAID SINGLE INLET TO THE TWO PRESSURE CHAMBERS, THE TWO SPRINGS BEING OF SUCH STRENGTH THAT WHEN PRESSURE MEDIUM IS INTRODUCED THE LOWERING OF SAID KNIFE TAKES PLACE PRIOR TO THE SIDE SETTING THEREOF, WHILE WHEN PRESSURE OF THE PRESSURE MEDIUM IS RELEASED A REVERSE SIDE MOVEMENT OF THE KNIFE TAKES PLACE PRIOR TO THE RAISING THEREOF, AND AT LEAST ONE PLATE SPRING ADJUSTABLY ENGAGING SAID KNIFE AND SAID HUB. 